Design. Study subjects will include 60 male and female patients with mild-moderate AD. In a randomized, placebo-controlled trial, two doses of CY or rofecoxib will be compared over a 6-month period. While the primary outcome measures will be safety and immunologic data, cognitive and other behavioral measures will also be collected. The biological outcome measures will include measures of brain volume (assessed by magnetic resonance imaging) and cerebrospinal fluid biomarkers of neurodegeneration, neuroinflammation, and neuroimmune activation. In addition, peripheral lymphocyte subsets and peripheral markers of inflammation will be assessed. This design is meant to provide dose-finding data to help design a more definitive efficacy trial with CY if the safety/tolerability parameters are acceptable in this pilot study.